Donald Trump has accused incumbent President Barack Obama of making inflammatory statements and erecting roadblocks as his administration-in-waiting prepares to assume office.
In the weeks since Obama hosted the President-elect and Melania Trump to the White House, Trump has been largely complimentary about Obama.
But two days after Obama suggested in a radio broadcast that be believed he would have beaten Mr Trump had he been able to run for a third time, the 70-year-old tycoon responded stridently.
“Doing my best to disregard the many inflammatory President O statements and roadblocks.Thought it was going to be a smooth transition – NOT,” Trump wrote.
The latest Twitter tirade, delivered on Wednesday, he also criticised the Obama administration’s latest moves in regard to Israel and its decision the passing of a UN Security Council resolution that rebuked it over its building of Jewish settlements in Palestinian territories.
Historically, the US has used its veto power to block such criticisms.
But in what was widely seen as Obama’s final riposte to Israeli leader Benjamin Netanyahu, the US abstained instead.
The decision was immediately criticised by Netanyahu, and Trump, who said things would be different once he assumed office on January 20.
On Wednesday, Trump renewed that criticism.
“We cannot continue to let Israel be treated with such total disdain and disrespect. They used to have a great friend in the US,” he wrote.
“But not anymore. The beginning of the end was the horrible Iran deal, and now this (UN)! Stay strong Israel, January 20th is fast approaching.”
In an interview broadcast earlier this week. Obama said he believed that had he been able to run for a third term, he would be have been beaten Mr Trump.
Talking to David Axelrod, his friend and former adviser, he said: “I’m confident that if I – if I had run again and articulated it, I think I could’ve mobilised a majority of the American people to rally behind it.”
He added: “I know that in conversations that I’ve had with people around the country, even some people who disagreed with me, they would say the vision, the direction that you point towards is the right one.”